Undo item disposition after journal posted but packing slip not posted yet

Hi,

Using dynamics ax 2009 a RMA was returned and all 8 lines of the IAJ were dispositioned as Replace and Credit. The journal was then posted. The next step of posting the packing slip was not started yet. I do not want this customer to get replacement items and a credit, the intended action was to disposition as ‘credit’ putting our items back in stock and issuing the credit to the customer. How would I go about changing these after the IAJ was posted? Thank you very much.